"""Composition root: the one place that knows how the whole agent fits together.

Every component below has been unit-tested in isolation for some time; nothing
had ever assembled them. That gap hid two live bugs — the delegation harness
and the Gitea comment poller were both fully built and reachable from nothing
but their own tests — which is the argument for having a single root rather
than constructing pieces ad hoc.
"""

import threading
from collections.abc import Callable
from dataclasses import dataclass

from nisse_dev.approvals import PlanBoard
from nisse_dev.config import AgentConfig
from nisse_dev.control import Orchestrator
from nisse_dev.delegation import Delegation
from nisse_dev.executor import LLMExecutor
from nisse_dev.expert import ExpertDesk
from nisse_dev.git import GitRepo, authenticated_url
from nisse_dev.gitea import Comment, GiteaClient
from nisse_dev.llm import AnthropicPassthroughClient, LiteLLMClient
from nisse_dev.matrix import MatrixTransport
from nisse_dev.oplog import OpLog
from nisse_dev.planner import LLMPlanningAgent
from nisse_dev.poller import CommentPoller
from nisse_dev.publish import MilestonePublisher
from nisse_dev.state import StateStore
from nisse_dev.tools import Workspace


@dataclass
class Agent:
    config: AgentConfig
    store: StateStore
    transport: MatrixTransport
    orchestrator: Orchestrator
    gitea: GiteaClient
    account: str
    _stopped: threading.Event

    def start(self) -> None:
        """Boot in the order A3 requires: reconcile against external truth
        before accepting a single operator command."""
        self.orchestrator.start()
        self.transport.start()
        state = self.store.get_state()
        where = state.state if state else "IDLE"
        self.transport.send_message(
            f"nisse-dev up as {self.account} — project {self.config.project}, "
            f"state {where}, planner {self.config.roles.planner}, "
            f"executor {self.config.roles.executor}"
        )

    def wait(self) -> None:
        self._stopped.wait()

    def stop(self) -> None:
        """Shut down outermost-first: stop accepting work, then stop talking,
        then close the state store last so nothing writes to a closed file."""
        self.orchestrator.stop_watching()
        self.transport.close()
        self.gitea.close()
        self.store.close()
        self._stopped.set()


def prepare_workspace(config: AgentConfig, account: str) -> GitRepo:
    """Ensure the workspace is a clone of the project repo.

    Cloning here rather than on `use <project>` is the single-project
    shortcut: resolving a project name to a repo is issue #27's work.
    """
    repo = GitRepo(config.workspace)
    remote = authenticated_url(
        config.gitea_url, config.gitea_repo, account, config.gitea_token
    )
    if not (config.workspace / ".git").exists():
        config.workspace.parent.mkdir(parents=True, exist_ok=True)
        GitRepo(config.workspace.parent).clone(remote, config.workspace)
    repo.configure_identity(account, f"{account}@users.noreply.local")
    return repo


def build_agent(
    config: AgentConfig, *, notify: Callable[[str], None] | None = None
) -> Agent:
    oplog = OpLog("nisse-dev")
    store = StateStore(config.state_db, oplog=oplog)

    gitea = GiteaClient(config.gitea_url, config.gitea_token)
    # Whoami rather than another config variable: it names the identity every
    # Gitea permission is evaluated against, and proves the token works before
    # anything depends on it.
    account = gitea.whoami()

    git_repo = prepare_workspace(config, account)
    workspace = Workspace(config.workspace)

    normalized = LiteLLMClient(config.llm_base_url, config.llm_token)
    # Delegations take the passthrough route; fidelity is cheap elsewhere (A5).
    passthrough = AnthropicPassthroughClient(config.llm_base_url, config.llm_token)

    transport = MatrixTransport(config.matrix)
    announce = notify or transport.send_message

    expert = ExpertDesk(normalized, store, config.roles)
    delegation = Delegation(
        passthrough,
        store,
        workspace,
        git_repo,
        model=config.roles.resolve("delegate"),
    )
    executor = LLMExecutor(
        normalized,
        store,
        config.roles,
        workspace,
        expert=expert,
        delegate=delegation,
        notify=announce,
    )
    publisher = MilestonePublisher(
        store,
        gitea,
        config.gitea_repo,
        git_repo,
        base_url=config.gitea_url,
        account=account,
        token=config.gitea_token,
        base_branch=config.base_branch,
    )

    def poller_factory(on_comment: Callable[[Comment], None]) -> CommentPoller:
        return CommentPoller(
            gitea,
            config.gitea_repo,
            on_comment,
            oplog=oplog,
            # Its own comments are not new input; without this the agent
            # answers itself.
            ignore_authors={account},
        )

    orchestrator = Orchestrator(
        store,
        transport,
        LLMPlanningAgent(normalized, store, config.roles),
        operators=config.operators,
        roles=config.roles,
        executor=executor,
        publisher=publisher,
        gitea_operators=config.gitea_operators,
        board=PlanBoard(gitea, config.gitea_repo),
        delegate=delegation,
        poller_factory=poller_factory,
    )
    return Agent(
        config=config,
        store=store,
        transport=transport,
        orchestrator=orchestrator,
        gitea=gitea,
        account=account,
        _stopped=threading.Event(),
    )